Detection of Heavy Cosmic Ray Particle (Z > 20) at Hanle, Ladakh at an Alti-tude of 4.5 km a.s.l. using SSNTD.

摘要

To detect exotic events, like strangelets, expected to be present in the cosmic ray flux at high altitude, wehave placed Solid State Nuclear Track Detectors of the material Polyethylene Terephthalate (PET) with a high detectionthreshold along with standard CR-39 at different mountain altitudes. Geographical locations chosen are Darjeeling (La-titude- 28° N, Longitude - 88° E and Altitude 2.13 km), Ooty (Latitude - 11 °24 'N,Longitude - 76 °42 'E and Alt itude2.23 km) and Hanle (Latitude- 32o42 'N,Longitude - 79o04 'E,Altitude 4.5 km).The flux of recor ded tracks at Hanley is~10-5/ (cm2/s/sr) on PET and flux observed in CR-39 ~ is 10-3/ (cm2/s/sr); both these values are consistent with thefluxes obtained at other locations. These tracks are due to mainly protons and low energy ions. One high energy heavyion Z > 20 has been recorded at Hanley which punched through 0.7mm thick CR-39 plate. Track parameters and theratio of track etch rate and bulk etch rate (Vt/Vg) for this event are remarkably different from those of the other tracks,making it a candidate for exotic event.